Heat the olive oil in a large pot over medium heat.
Add the diced onions and sauté until translucent, about 5 minutes.
Stir in the minced garlic and diced bell pepper; cook for 2-3 minutes until fragrant.
Add the can of diced tomatoes, chicken broth, cumin, chili powder, salt, and pepper; stir to combine.
Bring the soup to a simmer, then reduce the heat and cover; let it cook for 20-25 minutes.
Add the chicken breasts to the pot, submerging them in the liquid.
Continue to simmer with the chicken for an additional 15 minutes until cooked through.
Remove the chicken from the pot, shred it with two forks, and return it to the soup.
Add corn and any preferred spices to the soup, adjusting the seasoning as necessary.
Garnish with tortilla strips, avocado, cilantro, and lime wedges before serving.